Water closet tank



FIG. 1 is a top perspective view of a water closet tank showing our new design;

FIG. 2 is a front elevational view thereof, the rear elevational view being the mirror image thereof;

FIG. 3 is a left side elevational view thereof, the right side being the mirror image of the left side;

FIG. 4 is a top plan view thereof; and

FIG. 5 is a bottom plan view thereof.

The broken line representations of fitting holes in FIG. 5 are for purposes of illustration only. 

The ornamental design for a water closet tank, as shown and described. 